Colonial Trade Pattern, North Atlantic, 18th Century
By the early 18th century, a complex network of colonial trade was established over the North Atlantic Ocean. This network was partially the result of local economic conditions and of dominant wind and sea current patterns. It was discovered in the 15th century, notably after the voyages of Columbus, that there is a circular wind and sea current pattern over the North Atlantic. The eastward wind pattern, which blows on the southern part, came to be known as the "trade winds" since they enabled to cross the Atlantic. The westward wind pattern, blowing on the northern part, came to be known as the "westerlies". The system is known as the North Atlantic Gyre, which the Gulf Stream is a part of and acts as a gigantic conveyor belt.
Since sailing ships were highly constrained by dominant wind patterns, a trade system followed this pattern. Manufactured commodities were exported from Europe, some towards African colonial centers where they would be used to purchase slaves, and some towards the American colonies. This system also included a slave trade, mainly to Central and South American colonies (Brazil, West Indies), where there was a high demand for labor in plantations and mines. Tropical commodities (e.g. sugar, molasses) produced in plantations flowed to the American colonies and to Europe. North America also exported tobacco, furs, indigo (a dye) and lumber (for shipbuilding) to Europe. This system of trade collapsed in the 19th century with the introduction of steamships, the end of slavery and the independence of many of the colonies of the Americas.